Milkvetch
is a perennial found throughout northern and
southwestern China and northern North America. It
is a perfect plant for cold, and arid to semi-arid
regions with poor or saline soils. It has a very
long tap root and can get water deep in the ground.
In China it is grown as fodder, green manure and
for soil conservation. Milk vetches are part of the
bean family (Fabaceae). In Latin, fab means
"bean".

Each plant
has a couple of stems that can grow to be 1.5 to 2
m tall. The leaves are each composed of 9 to 19
narrow leaflets, and are about 2 to 4 inches long
with soft hair all over them. The main tap root is
thick and has many roots growing off it. A
secondary root system starts about 20

cm. under the ground and can reach out to about 150 cm in
diameter. Nodules develop on the roots closer to the surface
from which new plants grow.

Milkvetch flowers
thoughout August. The lavender or bluish-purple flowers are
about 1/2 inch long and arranged in a dense cluster. The
cluster grows on a short stalk and can be cylindrical and
about 3 inches long. Seeds grow in a small, hairy pods that
turn black. The seeds are small and black and sometimes
rattle in the pod, giving some species of this plant the
name Rattle Pod.

One species of
Astragalus, Astragalus lentiginosus, contain the alkaloid
swainsonine, which can cause locoism. When animals eat this
astragalus their nervous systems become impaired, and they
become very excited when disturbed. Sometimes they died. In
the old days it used to be known as "loco weed".

A less deadly
variety of vetch can be found growing along our country's
highways as soil erosion control. In the spring the blue
flowers of vetch will carpet the sides of roads from New
Enland to California.